1. Field of the Invention
The present invention relates generally to a white light generating unit, a backlight assembly having the white light generating unit and a liquid crystal display device having the white light generating unit. More particularly, the present invention relates to a white light generating unit capable of generating a white light using a light emitting diode structure, a backlight assembly having the white light generating unit and a liquid crystal display device having the white light generating unit.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) device displays images using electrical and optical characteristics of liquid crystal installed therein. The LCD device has various advantages, for example, a thin thickness, small volume and light weight as compared with a cathode ray tube (CRT) device making it ideal for use in a variety of items, such as portable computers, communication devices, television sets, etc.
The LCD device includes a liquid crystal controlling unit that controls the liquid crystal, and a light providing unit that provides light to the liquid crystal. For example, the LCD device includes an LCD panel serving as the liquid crystal controlling unit and a backlight assembly functioning as the light providing unit.
The backlight assembly is employed for providing a planar light of a uniform luminance into the LCD panel. When such a light is incident into the LCD panel from the backlight assembly, a uniform image is displayed through an entire effective display area of the LCD panel.
The backlight assembly may include a light source that generates a light (e.g., a cold cathode fluorescent lamp (CCFL) having a cylindrical structure or a light emitting diode (LED) having a dot structure) and a light guiding plate. The LED is usually employed for a display device having a relatively small display unit, such as a mobile communication device, to thereby reduce a volume and a power consumption thereof.
A light generated from the LED typically corresponds to a point light. The point light is changed into a planar light in the light guiding plate to exit the light guiding plate through a light-exiting face. The light emitted from the light guiding plate is provided into the LCD panel to thereby display an image through the LCD panel. Preferably, the light emitted from the light guiding plate may be a white light, and thus the LED may correspond to a white LED or the light generated from the LED may be converted into the white light.
A conventional small or medium-sized display device includes a white LED. However, in the conventional display device, a light generated from the white LED is incident into the light guiding plate at a relatively small divergence angle resulting in a dark portion on the light guiding plate. Thus, the conventional display device requires a number of the white LEDs in order to maximize the effective display area of the display device. In addition, the white LED has a complex structure and is very expensive so that the conventional display device including the white LED may be increased in size thereby potentially increasing its cost of manufacturers.